database.js

require('dotenv').load();
const util = require('util');
const mysql = require('mysql')
const pool = mysql.createPool({
    host: process.env.DB_HOST,
    user: process.env.DB_USER,
    password: process.env.DB_PASSWORD,
    database: process.env.DB_NAME,
    connectionLimit: 10,
});

// Ping database to check for common exception errors.
pool.getConnection((err, connection) => {
    if (err) {
        if (err.code === 'PROTOCOL_CONNECTION_LOST') {
            console.error('Database connection was closed.');
        }
        if (err.code === 'ER_CON_COUNT_ERROR') {
            console.error('Database has too many connections.');
        }
        if (err.code === 'ECONNREFUSED') {
            console.error('Database connection was refused.');
        }
    }

    if (connection) connection.release();

    return;
})

// Promisify for Node.js async/await.
pool.query = util.promisify(pool.query);

module.exports = pool;